如何从Firebase检索此数据? [英] How to retrive this data from firebase?

问题描述

我如何从所有用户ID未知的医院中检索所有医院名称.

how can i retrieve all hospitalNames from Hospitals where all userIds are unknown.

推荐答案

如何?

final FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference ref = database.getReference("medicine/Hospitals");
ref.addValueEventListener(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        hospitalArrayList.clear();
        for (DataSnapshot item : dataSnapshot.getChildren()) {
            Hospital hospital = item.getValue(Hospital.class);
            hospitalArrayList.add(hospital);
            System.out.println(hospital);
        }
        dataRetrieved();
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {
        System.out.println("The read failed: " + databaseError.getCode());
    }
});

private void dataRetrieved() {
    adapter.notifyDataSetChanged();
}

Hospital.java简单示例

Hospital.java simple example

public class Hospital {
    public HospitalData hospitalData;

    public Hospital(HospitalData hospitalData) { }

    public Hospital() { }

    public static class HospitalData {
        public String hospitalName;
        public String hospitalAddress;

        public HospitalData(String hospitalName, String hospitalAddress) { }

        public HospitalData() { }

    }

}

您可以像这样在适配器中使用它.

You can use this in adapter like this.

String name = hospitalArrayList.get(position).hospitalData.hospitalName;

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